Deforestation Impacts on Bat Functional Diversity in Tropical Landscapes

Functional diversity is the variability in the functional roles carried out by species within ecosystems. Changes in the environment can affect this component of biodiversity and can, in turn, affect different processes, including some ecosystem services. This study aimed to determine the effect of forest loss on species richness, abundance and functional diversity of Neotropical bats. To this end, we identified six landscapes with increasing loss of forest cover in the Huasteca region of the state of Hidalgo, Mexico. We captured bats in each landscape using mist nets, and calculated functional diversity indices (functional richness and functional evenness) along with species richness and abundance. We analyzed these measures in terms of percent forest cover. We captured 906 bats (Phyllostomidae and Mormoopidae), including 10 genera and 12 species. Species richness, abundance and functional richness per night are positively related with forest cover. Generalized linear models show that species richness, abundance and functional richness per night are significantly related with forest cover, while seasonality had an effect on abundance and functional richness. Neither forest cover nor season had a significant effect on functional evenness. All these findings were consistent across three spatial scales (1, 3 and 5 km radius around sampling sites). The decrease in species, abundance and functional richness of bats with forest loss may have implications for the ecological processes they carry out such as seed dispersal, pollination and insect predation, among others.功能多样性（functional diversity）指生态系统内各物种所承担的生态功能的变异程度。环境变化可影响生物多样性的这一组成部分，进而对包括部分生态系统服务在内的多种生态过程产生影响。本研究旨在探究森林丧失对新热带区蝙蝠（Neotropical bats）的物种丰富度、种群数量及功能多样性的影响。为此，我们在墨西哥伊达尔戈州瓦斯特卡地区选取了6个森林覆盖丧失程度依次递增的景观样区。我们在每个样区均采用雾网法捕获蝙蝠，并计算了功能多样性指数（functional diversity indices，包含功能丰富度（functional richness）与功能均匀度（functional evenness）），同时一并计算了物种丰富度与种群数量。我们以森林覆盖率为变量对上述指标开展分析。本次研究共捕获蝙蝠906只，隶属于叶口蝠科（Phyllostomidae）与矛吻蝠科（Mormoopidae），涵盖10个属、12个物种。夜间的物种丰富度、种群数量及功能丰富度均与森林覆盖率呈正相关关系。广义线性模型（generalized linear models）结果显示，夜间的物种丰富度、种群数量及功能丰富度均与森林覆盖率存在显著关联，而季节周期性则对种群数量与功能丰富度存在影响。森林覆盖率与季节均未对功能均匀度产生显著影响。上述所有研究结果在采样点周边1km、3km及5km半径这三个空间尺度上均保持一致。伴随森林丧失出现的蝙蝠物种丰富度、种群数量及功能丰富度下降，可能会对其承担的种子传播、授粉、昆虫捕食等各类生态过程造成潜在影响。